X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 10 Apr 2006 01:40:43 -0400 Message-ID: X-Original-Return-Path: Received: from apollo.email.starband.net ([148.78.247.132] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with ESMTP id 1063727 for lml@lancaironline.net; Mon, 10 Apr 2006 00:37:26 -0400 Received-SPF: none receiver=logan.com; client-ip=148.78.247.132; envelope-from=hwasti@starband.net Received: from starband.net (vsat-148-64-23-255.c050.t7.mrt.starband.net [148.64.23.255]) by apollo.email.starband.net (8.12.11/8.12.11) with ESMTP id k3A4aRpn026427 for ; Mon, 10 Apr 2006 00:36:36 -0400 X-Original-Message-ID: <4439E0C4.6070102@starband.net> X-Original-Date: Sun, 09 Apr 2006 21:36:20 -0700 From: "Hamid A. Wasti" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.0.2) Gecko/20021120 Netscape/7.01 X-Accept-Language: en-us, en MIME-Version: 1.0 X-Original-To: Lancair Mailing List Subject: Re: [LML] TSB Report on N750F References: Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV version 0.86.2, clamav-milter version 0.86 on apollo X-Virus-Status: Clean Craig Berland wrote:

Oh my...Oh my average decent of 12,000 ft per minute. Caused me to take 2 deep breaths.

The airplane broke up at a speed higher than 412KTS (Mach 0.62) in a steep dive. 400KTS is about 40,000 FPM. In a steep dive, the descent rate would be a significant fraction of that. As scary as the average descent rate is, the terminal rate was several times higher.

While we are talking scary, think about the following scenario:

The pitot tube is blocked due to icing. The windshield may be iced over as well, blocking all outside references even if the airplane does break out into VMC.

The airplane is descending, causing the indicated airspeed to decrease (the difference between the increasing static pressure at lower altitudes and the "high pressure" air trapped in the pitot system is becoming less and less).

The pilot pushes the nose down making the dive steeper and decreasing the ground speed reported by the GPS. The decreasing ground speed correlates with the decreasing indicated airspeed. Even the unwinding altimeter could be interpreted as a stalled airplane in a descent by someone focused on a stall as the main problem.

Can an average pilot assess the situation with enough confidence to overcome all their training and cut the power and pull up when everything is pointing to a stall or an imminent stall? Can an average pilot do that in less time than it took you to read this post?

Regards,

Hamid